The holistic approach to heating

Amidst the current climate of rising fuel costs, Pete Mills, Commercial Technical Operations Manager at Bosch Commercial and Industrial Heating, explains how taking a more holistic approach to the provision of heating and hot water can result in maximum efficiency levels.


The impact of rising fuel costs is undoubtedly a hot topic in the building services industry. Given the potential for budgets to be stretched, we are regularly seeing instances where stakeholders are actively seeking alternative solutions which not only meet their energy requirements, but help to reduce costs.


The efficient provision of heating and hot water is often best found in a combination of technologies. A well thought out system can increase the likelihood of a favourable return on investment, which will in turn lead to quicker payback on the initial financial outlay.


Replacing to save


When it comes to boiler replacement projects, carrying out work to upgrade a system needn’t be intrusive. One solution definitely doesn’t fit all, but there are ways and means of integrating new condensing boilers into existing systems and pipework, without the risk of any contamination of the new boiler from the old heating system, therefore hampering performance.


Most modern high performance condensing boilers need to be installed as part of a sealed system, and those that don’t still benefit greatly from being separated from an ageing system where the water quality may be difficult to control. For certain applications, conversion from an open vented to a sealed system can be tough to achieve with potential leaks from old pipework and fittings to consider, as well as the possibility of corrosion problems if the water from an ageing system is allowed to circulate freely around a brand new condensing boiler.


In these cases, the most practical way of overcoming this kind of problem is to leave the existing system open vented whilst separating the boiler primary circuit using a stainless steel plate heat exchanger. Introducing a plate heat exchanger to the system ensures a safe and protected primary circuit for the new condensing boiler, whilst also ensuring there is no risk of system leaks from a higher sealed system pressure and eliminating any corrosion or restriction issues.


The key to ensuring the most effective technologies are selected is having a detailed understanding of the end-user’s requirements from the outset, which means a thorough specification process is required. The emphasis when selecting the technology should be less on focusing on a technology in isolation, and more on coming up with a winning combination that delivers the maximum benefit for the end user.


Aside from boilers, there are also a number of renewable technologies available on the market today, each of which has different strengths and limitations. Whilst renewable technologies can offer a short payback period in their own right, by combining with an existing boiler, the end-user can benefit from a system which harnesses free natural energy from the environment, with the boiler capable of meeting extra demand when it is particularly high.


Feel the power


For applications with sufficient demand for electricity as well as heat, the incorporation of a combined heat and power (CHP) module can prove worthwhile. As heat is produced as a by-product of the power generated and by distributing via a thermal store, the technology lends itself to operation alongside another heating source –a high efficiency boiler being one of the most common examples. In this case, the key to a successful systems alliance is that the system is designed to utilise 100% of the heat generated. To avoid the rejection or wastage of heat, it is absolutely essential that the CHP module is correctly sized.


In most cases, CHP units are installed in tandem with boilers, which provide back up during service periods. Whatever the arrangement, the key to reaping the benefits of a CHP system is to ensure it is sized to the thermal base load of a project, or 20% of the peak load, to allow for maximum efficiency. Whilst CHP will meet a building’s base heating load requirements most of the time, a secondary source will be required, to satisfy a building’s peak heating load.


The number of technologies offered by manufacturers today presents the building services engineer with a tough decision when it comes to investing in the efficient provision of heating and hot water. By taking a step back and looking at the system as a whole, there is potential for huge benefits to be reaped. A well thought out system design can not only meet the requirements of the application very effectively, but can also help to minimise fuel expenditure.


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